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8.17  References

Als-Nielsen 2004  
Als-Nielsen B, Gluud LL, Gluud C. Methodological quality and treatment effects in randomized trials: a review of six empirical studies.
12th Cochrane Colloquium, Ottawa (Canada), 2004.

Altman 1999  
Altman DG, Bland JM. How to randomize. BMJ 1999; 319: 703-704.

Balk 2002  
Balk EM, Bonis PAL, Moskowitz H, Schmid CH, Ioannidis JPA, Wang C, Lau J. Correlation of quality measures with estimates of treatment effect in meta-analyses of randomized controlled trials. JAMA 2002; 287: 2973-2982.

Bellomo 2000  
Bellomo R, Chapman M, Finfer S, Hickling K, Myburgh J. Low-dose dopamine in patients with early renal dysfunction: a placebo-controlled randomised trial. Australian and New Zealand Intensive Care Society (ANZICS) Clinical Trials Group. The Lancet 2000; 356: 2139-2143.

Berger 2003  
Berger VW, Ivanova A, Knoll MD. Minimizing predictability while retaining balance through the use of less restrictive randomization procedures. Statistics in Medicine 2003; 22: 3017-3028.

Berger 2005  
Berger VW. Quantifying the magnitude of baseline covariate imbalances resulting from selection bias in randomized clinical trials. Biometrical Journal 2005; 47: 119-127.

Berlin 1997  
Berlin JA. Does blinding of readers affect the results of meta-analyses? University of Pennsylvania Meta-analysis Blinding Study Group. The Lancet 1997; 350: 185-186.

Boutron 2005  
Boutron I, Estellat C, Ravaud P. A review of blinding in randomized controlled trials found results inconsistent and questionable. Journal of Clinical Epidemiology 2005; 58: 1220-1226.

Boutron 2006  
Boutron I, Estellat C, Guittet L, Dechartres A, Sackett DL, Hróbjartsson A, Ravaud P. Methods of blinding in reports of randomized controlled trials assessing pharmacologic treatments: a systematic review. PLOS Medicine 2006; 3: 1931-1939.

Brightling 2000  
Brightling CE, Monteiro W, Ward R, Parker D, Morgan MD, Wardlaw AJ, Pavord ID. Sputum eosinophilia and short-term response to prednisolone in chronic obstructive pulmonary disease: a randomised controlled trial. The Lancet 2000; 356: 1480-1485.

Brown 2005  
Brown S, Thorpe H, Hawkins K, Brown J. Minimization: reducing predictability for multi-centre trials whilst retaining balance within centre. Statistics in Medicine 2005; 24: 3715-3727.

Chan 2004a  
Chan AW, Hróbjartsson A, Haahr MT, Gøtzsche PC, Altman DG. Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles. JAMA 2004; 291: 2457-2465.

Chan 2004b  
Chan AW, Krleža-Jeric K, Schmid I, Altman DG. Outcome reporting bias in randomized trials funded by the Canadian Institutes of Health Research. Canadian Medical Association Journal 2004; 171: 735-740.

Chan 2005  
Chan AW, Altman DG. Identifying outcome reporting bias in randomised trials on PubMed: review of publications and survey of authors. BMJ 2005; 330: 753.

Coronary Drug Project Research Group 1980  
Coronary Drug Project Research Group. Influence of adherence to treatment and response of cholesterol on mortality in the coronary drug project. New England Journal of Medicine 1980; 303: 1038-1041.

Cuellar 2000  
Cuellar GEM, Ruiz AM, Monsalve MCR, Berber A. Six-month treatment of obesity with sibutramine 15 mg; a double-blind, placebo-controlled monocenter clinical trial in a Hispanic population. Obesity Research 2000; 8: 71-82.

de Gaetano 2001  
de Gaetano G. Low-dose aspirin and vitamin E in people at cardiovascular risk: a randomised trial in general practice. Collaborative Group of the Primary Prevention Project. The Lancet 2001; 357: 89-95.

Detsky 1992  
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbe KA. Incorporating variations in the quality of individual randomized trials into meta-analysis. Journal of Clinical Epidemiology 1992; 45: 255-265.

Devereaux 2001  
Devereaux PJ, Manns BJ, Ghali WA, Quan H, Lacchetti C, Montori VM, Bhandari M, Guyatt GH. Physician interpretations and textbook definitions of blinding terminology in randomized controlled trials. JAMA 2001; 285: 2000-2003.

Emerson 1990  
Emerson JD, Burdick E, Hoaglin DC, Mosteller F, Chalmers TC. An empirical study of the possible relation of treatment differences to quality scores in controlled randomized clinical trials. Controlled Clinical Trials 1990; 11: 339-352.

Fergusson 2002  
Fergusson D, Aaron SD, Guyatt G, Hébert P. Post-randomisation exclusions: the intention to treat principle and excluding patients from analysis. BMJ 2002; 325: 652-654.

Fergusson 2004  
Fergusson D, Glass KC, Waring D, Shapiro S. Turning a blind eye: the success of blinding reported in a random sample of randomised, placebo controlled trials. BMJ 2004; 328: 432.

Furukawa 2007  
Furukawa TA, Watanabe N, Omori IM, Montori VM, Guyatt GH. Association between unreported outcomes and effect size estimates in Cochrane meta-analyses. JAMA 2007; 297: 468-470.

Ghersi 2006  
Ghersi D, Clarke M, Simes J. Selective reporting of the primary outcomes of clinical trials: a follow-up study.
14th Cochrane Colloquium, Dublin (Ireland), 2006.

Gøtzsche 1996  
Gøtzsche PC. Blinding during data analysis and writing of manuscripts. Controlled Clinical Trials 1996; 17: 285-290.

Gøtzsche 2006  
Gøtzsche PC, Hróbjartsson A, Johansen HK, Haahr MT, Altman DG, Chan AW. Constraints on publication rights in industry-initiated clinical trials. JAMA 2006; 295: 1645-1646.

Gøtzsche 2007  
Gøtzsche PC, Hróbjartsson A, Maric K, Tendal B. Data extraction errors in meta-analyses that use standardized mean differences. JAMA 2007; 298: 430-437.

Greenland 2001  
Greenland S, O'Rourke K. On the bias produced by quality scores in meta-analysis, and a hierarchical view of proposed solutions. Biostatistics 2001; 2: 463-471.

Guyatt 2008  
Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, Schünemann HJ. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 2008; 336: 924-926.

Haahr 2006  
Haahr MT, Hróbjartsson A. Who is blinded in randomised clinical trials? A study of 200 trials and a survey of authors. Clinical Trials 2006; 3: 360-365.

Hahn 2002  
Hahn S, Williamson PR, Hutton JL. Investigation of within-study selective reporting in clinical research: follow-up of applications submitted to a local research ethics committee. Journal of Evaluation in Clinical Practice 2002; 8: 353-359.

Hansson 1999  
Hansson L, Lindholm LH, Niskanen L, Lanke J, Hedner T, Niklason A, Luomanmaki K, Dahlof B, de Faire U, Morlin C, Karlberg BE, Wester PO, Bjorck JE. Effect of angiotensin-converting-enzyme inhibition compared with conventional therapy on cardiovascular morbidity and mortality in hypertension: the Captopril Prevention Project (CAPPP) randomised trial. The Lancet 1999; 353: 611-616.

Hill 1990  
Hill AB. Memories of the British streptomycin trial in tuberculosis: the first randomized clinical trial. Controlled Clinical Trials 1990; 11: 77-79.

Hollis 1999  
Hollis S, Campbell F. What is meant by intention to treat analysis? Survey of published randomised controlled trials. BMJ 1999; 319: 670-674.

Hróbjartsson 2007  
Hróbjartsson A, Forfang E, Haahr MT, ls-Nielsen B, Brorson S. Blinded trials taken to the test: an analysis of randomized clinical trials that report tests for the success of blinding. International Journal of Epidemiology 2007; 36: 654-663.

Hutton 2000  
Hutton JL, Williamson PR. Bias in meta-analysis due to outcome variable selection within studies. Journal of the Royal Statistical Society Series C 2000; 49: 359-370.

Jadad 1996  
Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJM, Gavaghan DJ, McQuay H. Assessing the quality of reports of randomized clinical trials: Is blinding necessary? Controlled Clinical Trials 1996; 17: 1-12.

Johansen 2000  
Johansen HK, Gøtzsche PC. Amphotericin B lipid soluble formulations versus amphotericin B in cancer patients with neutropenia. Cochrane Database of Systematic Reviews 2000, Issue 3. Art No: CD000969.

Jørgensen 2006  
Jørgensen KJ, Johansen HK, Gøtzsche PC. Voriconazole versus amphotericin B in cancer patients with neutropenia. Cochrane Database of Systematic Reviews 2006, Issue 1. Art No: CD004707.

Jørgensen 2007  
Jørgensen KJ, Johansen HK, Gøtzsche PC. Flaws in design, analysis and interpretation of Pfizer's antifungal trials of voriconazole and uncritical subsequent quotations. Trials 2007; 7: 3.

Jüni 1999  
Jüni P, Witschi A, Bloch R, Egger M. The hazards of scoring the quality of clinical trials for meta-analysis. JAMA 1999; 282: 1054-1060.

Jüni 2001  
Jüni P, Altman DG, Egger M. Systematic reviews in health care: Assessing the quality of controlled clinical trials. BMJ 2001; 323: 42-46.

Kjaergard 2001  
Kjaergard LL, Villumsen J, Gluud C. Reported methodologic quality and discrepancies between large and small randomized trials in meta-analyses. Annals of Internal Medicine 2001; 135: 982-989.

Lachin 2000  
Lachin JM. Statistical considerations in the intent-to-treat principle. Controlled Clinical Trials 2000; 21: 167-189.

Marshall 2000  
Marshall M, Lockwood A, Bradley C, Adams C, Joy C, Fenton M. Unpublished rating scales: a major source of bias in randomised controlled trials of treatments for schizophrenia. British Journal of Psychiatry 2000; 176: 249-52..

Melander 2003  
Melander H, Ahlqvist-Rastad J, Meijer G, Beermann B. Evidence b(i)ased medicine - selective reporting from studies sponsored by pharmaceutical industry: review of studies in new drug applications. BMJ 2003; 326: 1171-1173.

Moher 1995  
Moher D, Jadad AR, Nichol G, Penman M, Tugwell P, Walsh S. Assessing the quality of randomized controlled trials: An annotated bibliography of scales and checklists. Controlled Clinical Trials 1995; 16: 62-73.

Moher 1996  
Moher D, Jadad AR, Tugwell P. Assessing the quality of randomized controlled trials: Current issues and future directions. International Journal of Technology Assessment in Health Care 1996; 12: 195-208.

Moher 1998  
Moher D, Pham B, Jones A, Cook DJ, Jadad AR, Moher M, Tugwell P, Klassen TP. Does quality of reports of randomised trials affect estimates of intervention efficacy reported in meta-analyses? The Lancet 1998; 352: 609-613.

Moher 2001  
Moher D, Schulz KF, Altman DG. The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomised trials. The Lancet 2001; 357: 1191-1194.

Montori 2002  
Montori VM, Bhandari M, Devereaux PJ, Manns BJ, Ghali WA, Guyatt GH. In the dark: the reporting of blinding status in randomized controlled trials. Journal of Clinical Epidemiology 2002; 55: 787-790.

Naylor 1997  
Naylor CD. Meta-analysis and the meta-epidemiology of clinical research. BMJ 1997; 315: 617-619.

Newell 1992  
Newell DJ. Intention-to-treat analysis: implications for quantitative and qualitative research. International Journal of Epidemiology 1992; 21: 837-841.

Noseworthy 1994  
Noseworthy JH, Ebers GC, Vandervoort MK, Farquhar RE, Yetisir E, Roberts R. The impact of blinding on the results of a randomized, placebo-controlled multiple sclerosis clinical trial. Neurology 1994; 44: 16-20.

Oxman 1993  
Oxman AD, Guyatt GH. The science of reviewing research. Annals of the New York Academy of Sciences 1993; 703: 125-133.

Peto 1999  
Peto R. Failure of randomisation by "sealed" envelope. The Lancet 1999; 354: 73.

Pildal 2007  
Pildal J, Hróbjartsson A, Jørgensen KJ, Hilden J, Altman DG, Gøtzsche PC. Impact of allocation concealment on conclusions drawn from meta-analyses of randomized trials. International Journal of Epidemiology 2007; 36: 847-857.

Porta 2007  
Porta N, Bonet C, Cobo E. Discordance between reported intention-to-treat and per protocol analyses. Journal of Clinical Epidemiology 2007; 60: 663-669.

Rees 2005  
Rees JR, Wade TJ, Levy DA, Colford JM, Jr., Hilton JF. Changes in beliefs identify unblinding in randomized controlled trials: a method to meet CONSORT guidelines. Contemporary Clinical Trials 2005; 26: 25-37.

Sackett 2007  
Sackett DL. Commentary: Measuring the success of blinding in RCTs: don't, must, can't or needn't? International Journal of Epidemiology 2007; 36: 664-665.

Safer 2002  
Safer DJ. Design and reporting modifications in industry-sponsored comparative psychopharmacology trials. Journal of Nervous and Mental Disease 2002; 190: 583-592.

Schulz 1995a  
Schulz KF. Subverting randomization in controlled trials. JAMA 1995; 274: 1456-1458.

Schulz 1995b  
Schulz KF, Chalmers I, Hayes RJ, Altman DG. Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials. JAMA 1995; 273: 408-412.

Schulz 1996  
Schulz KF, Grimes DA, Altman DG, Hayes RJ. Blinding and exclusions after allocation in randomised controlled trials: survey of published parallel group trials in obstetrics and gynaecology. BMJ 1996; 312: 742-744.

Schulz 2002a  
Schulz KF, Chalmers I, Altman DG. The landscape and lexicon of blinding in randomized trials. Annals of Internal Medicine 2002; 136: 254-259.

Schulz 2002b  
Schulz KF, Grimes DA. Allocation concealment in randomised trials: defending against deciphering. The Lancet 2002; 359: 614-618.

Schulz 2002c  
Schulz KF, Grimes DA. Generation of allocation sequences in randomised trials: chance, not choice. The Lancet 2002; 359: 515-519.

Schulz 2002d  
Schulz KF, Grimes DA. Unequal group sizes in randomised trials: guarding against guessing. The Lancet 2002; 359: 966-970.

Schulz 2006  
Schulz KF, Grimes DA. The Lancet Handbook of Essential Concepts in Clinical Research. Edinburgh (UK): Elsevier, 2006.

Schulz 2010  
Schulz KF, Altman DG, Moher D, CONSORT Group. CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials. BMJ 2010; 340: c332.

Senn 1991  
Senn S. Baseline comparisons in randomized clinical trials. Statistics in Medicine 1991; 10: 1157-1159.

Siersma 2007  
Siersma V, ls-Nielsen B, Chen W, Hilden J, Gluud LL, Gluud C. Multivariable modelling for meta-epidemiological assessment of the association between trial quality and treatment effects estimated in randomized clinical trials. Statistics in Medicine 2007; 26: 2745-2758.

Smilde 2001  
Smilde TJ, van Wissen S, Wollersheim H, Trip MD, Kastelein JJ, Stalenhoef AF. Effect of aggressive versus conventional lipid lowering on atherosclerosis progression in familial hypercholesterolaemia (ASAP): a prospective, randomised, double-blind trial. The Lancet 2001; 357: 577-581.

Spiegelhalter 2003  
Spiegelhalter DJ, Best NG. Bayesian approaches to multiple sources of evidence and uncertainty in complex cost-effectiveness modelling. Statistics in Medicine 2003; 22: 3687-3709.

Sterne 2002  
Sterne JA, Jüni P, Schulz KF, Altman DG, Bartlett C, Egger M. Statistical methods for assessing the influence of study characteristics on treatment effects in 'meta-epidemiological' research. Statistics in Medicine 2002; 21: 1513-1524.

Tierney 2005  
Tierney JF, Stewart LA. Investigating patient exclusion bias in meta-analysis. International Journal of Epidemiology 2005; 34: 79-87.

Turner 2008  
Turner RM, Spiegelhalter DJ, Smith GCS, Thompson SG. Bias modelling in evidence synthesis.
Journal of the Royal Statistical Society Series A  2008 (published online ahead of print, 8 July 2008).

Unnebrink 2001  
Unnebrink K, Windeler J. Intention-to-treat: methods for dealing with missing values in clinical trials of progressively deteriorating diseases. Statistics in Medicine 2001; 20: 3931-3946.

Vickers 2001  
Vickers AJ. The use of percentage change from baseline as an outcome in a controlled trial is statistically inefficient: a simulation study. BMC Medical Research Methodology 2001; 1: 6.

von Elm 2006  
von Elm E, Röllin A, Blümle A, Senessie C, Low N, Egger M. Selective reporting of outcomes of drug trials. Comparison of study protocols and pulbished articles. 14th Cochrane Colloquium, Dublin (Ireland), 2006.

Williamson 2005a  
Williamson PR, Gamble C. Identification and impact of outcome selection bias in meta-analysis. Statistics in Medicine 2005; 24: 1547-1561.

Williamson 2005b  
Williamson PR, Gamble C, Altman DG, Hutton JL. Outcome selection bias in meta-analysis. Statistical Methods in Medical Research 2005; 14: 515-524.

Wood 2004  
Wood AM, White IR, Thompson SG. Are missing outcome data adequately handled? A review of published randomized controlled trials in major medical journals. Clinical Trials 2004; 1: 368-376.

Wood 2008  
Wood L, Egger M, Gluud LL, Schulz K, Jüni P, Altman DG, Gluud C, Martin RM, Wood AJG, Sterne JAC. Empirical evidence of bias in treatment effect estimates in controlled trials with different interventions and outcomes: meta-epidemiological study.
BMJ 2008; 336: 601-605.

Woods 1995  
Woods KL. Mega-trials and management of acute myocardial infarction. The Lancet 1995; 346: 611-614.